Jets or Sharks (4)
I believe the answer is:
gang
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">jets or sharks</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for gang that I've seen before include "Posse" , "crowd" , "Work, criminal, group" , "Organised group of labourers" , "Working group or mob of hoodlums" .)